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Experiences with the QWEST/SCinet Bandwidth Challenge 2000-2002. John Shalf, Wes Bethel LBNL. Shaky City. Data Caches. HPC Resources. Simulations. Sensor Nets. STM. Collaborators. Handheld Devices. Dr Jane. Backend. Source Volume. Viewer Component. Visapult Architecture. Source
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Experiences with theQWEST/SCinet Bandwidth Challenge2000-2002 John Shalf, Wes Bethel LBNL
Shaky City Data Caches HPC Resources Simulations Sensor Nets STM Collaborators Handheld Devices Dr Jane
Backend Source Volume Viewer Component Visapult Architecture
Source Volume Visapult Architecture 3D 2D
Source Volume Visapult Architecture 3D Gigabits 2D Megabits
Source Volume Visapult Architecture 3D Gigabits 2D Megabits
Refactoring the Design • Congestion avoidance • Good for internet • Bad bad baaaad for PVCs and other dedicated networks. (switched lambdas?) • Multistream TCP • Erratic performance • Requires a lot of tuning • Unfriendly to other users • Unfriendly to visualization applications • We want full control of the “throttle” • Very much like network video
Refactoring the Design • TCP is the wrong thing for interactive vis! • Layer 3 latency/jitter (all buffering effects) • Poor response to bursty traffic • Vis needs interactivity and minimal latency! • Network Video / UDP streams • Present packets immediately (low latency) • Full control of data rate • Lossy, but effects of loss can be managed • SOCK_RDM
SC2001 BWC Results • 3.3 Gigabits Peak (MRTG of ESNet/QWEST OC-48) • Lots of time spent tuning (packet pacing is nontrivial)
SC2002 Planning • Better UDP packet pacing with poor clock granularity • Error diffusion algorithm from dithering • Omnidirectional viewing for Visapult • Nascent Grid Infrastructure • Global Grid Testbed Collaboration (GGTC) • GGTC won 3 out of 4 HPC challenge awards
Why do we do this?? • Opportunity to test the next generation network capacity (2 years before production) • Opportunity to test software ideas that will be required to make use of the next generation network (2 year lead) • Opportunity to test future network engineers (give them a 2 year lead on the problems with future networks) • Prescient • I-Way 1995 (presaged vBNS experiences and “The Grid”) • 1997 multi-stream tests (presaged multi-stream TCP protocols) • 2001 10GigE and UDP-based protocols • 10GigE backbone for SC2002 • RUDP, SABUL, TSUNAMI
What should you know for 2003 • Manual throttle (UDP-based protocols) are here to stay. • Hopefully SOCK_RDM will cover most needs • Whaaa? Those idiots are going to burn down the network! Next big thing is resource management • RSVP & DiffServ were developed to manage this very situation with regard to network video • RSVP & DiffServ are never going to happen • Gregory Bell, “Failure to Thrive: QoS and the Culture of Operational Networking,” Proceedings of the ACM SIGCOMM 2003 Workshops, RIPQoS Workshop. • Next Big Thing? : Pluggable Congestion Management • AIMD for internet (can even mimic multistream TCP behavior) • Fixed rate for PVCs and switched lambdas • Get hints from monitoring services (NWS) to manage flow end-to-end
Concern about the future of BWC • The future and eternal reigning champion of the BWC?
Concern about the future of BWC • The future and eternal reigning champion of the BWC? iperf --udp -b <infinity>
Concern about the future of BWC • The future and eternal reigning champion of the BWC? • How do we prevent this?
Concern about the future of BWC • The future and eternal reigning champion of the BWC? • How do we prevent this? • There is not technical solution to this problem • It is a social problem, not a technical one
Concern about the future of BWC • The future and eternal reigning champion of the BWC? • How do we prevent this? • There is not technical solution to this problem • Can’t ban UDP • Can’t eliminate high bandwidth category
Concern about the future of BWC • The future and eternal reigning champion of the BWC? • How do we prevent this? • There is not technical solution to this problem • Can’t ban UDP • Can’t eliminate high bandwidth category • Must answer • Does this advance science or art? • Is this a glimpse of the future?
Concern about the future of BWC • The future and eternal reigning champion of the BWC? • How do we prevent this? • There is not technical solution to this problem • Can’t ban UDP • Can’t eliminate high bandwidth category • Must answer • Does this advance science or art? • Is this a glimpse of the future? • What the heck are judges for anyways?
Wes Bethel Brian Tierney Dan Gunter Jason Lee Eli Dart Mike Bennett Chip Smith John Christman Raju Shah Ed Seidel Gabrielle Allen Tom Goodale Thomas Radke Tom Goodale Mirek Ruda Ludek Matskya Acknowledgements • NERSC • LBNL • NCSA • PSC • ANL • AEI/Potsdam • University of Amsterdam • ESNet • QWEST • Abilene • StarLight • Teragrid • Force10 Networks • Scinet
More Information • Visapult: • V1.0: http://vis.lbl.gov/projects/visapult • V2.0: http://vis.lbl.gov/projects/visapult2 • Cactus • http://www.cactuscode.org • VisPortal (Grid Portal for managing Visapult) • http://frost.lbl.gov/visportal/ • SC2002 Global Grid Testbed • http://scb.ics.muni.cz/static/SC2002/Testbed.html • Related Publications • Special Issue on Visualization on the Grid, IEEE Computer Graphics and Applications, Volume 23, Number 2, March/April 2003.